Nucleotide sequence and analysis of plasmid pMD136 from Pediococcus pentosaceus FBB61 (ATCC43200) involved in Pediocin A production

The complete sequence of the 19515-bp plasmid pMD136 from Pediococcus pento saceus FBB61 (ATCC43200) has been determined. This plasmid is involved in P ediocin A production, a bacteriocin active against a wide range of gram-pos itive bacteria. It appears to replicate via a theta mechanism, with structu res closely related to those of many lactococcal plasmids. Genes homologous to mobilization functions are also present, which are similar in sequence and arrangement to mobA, mobB, and mobC of some staphylococcal plasmids, al though the last one contains a deletion in its central part. The region inv olved in bacteriocin activity has been limited to a 9.4-kb fragment, contai ning 10 open reading frames organized in a single operon. Since Pediocin A has a molecular weight of about 80 kDa (Piva and Headon, Microbiology, 140, 697-702, 1994), and a gene long enough to encode it is not present in pMD1 36, it is proposed that genes residing on the plasmid are responsible for t he regulation of bacteriocinogenic activity. Gene arrangement and sequence homologies suggest the presence of a two-component-like regulatory mechanis m, (C) 2000 Academic Press.